For turning rotationally symmetrical elements such as wooden spindles or balustrades, a workpiece mounted in chucks is spun and a knife or set of knives is urged towards the work in a controlled manner, causing wood located outside the desired profile to be chipped away. In high speed work, the knives themselves are not held manually, but are themselves mounted on a rotary shaft which is urged transversely relatively towards the workpiece while spinning. (Actually, the spinning workpiece may be moved transversely towards the set of rotating knives.) In the language of the trade, the rotating shaft on which the knives are mounted is termed an arbor, and the set of knives, including the structure by means of which they are mounted to the arbor, is termed a cutterhead.
Although various features of cutterheads have been improved through the years, some detrimental characteristics have remained wanting improvement. Among these are the difficulty of easily and reliably mounting a cutterhead on an arbor so that it is accurately coaxial, easily and reliably mounting knife carriers on the cylinder of the cutterhead, preventing elements from being radially thrown out from the rotating cutterhead should an operator or set-up person neglect to tighten everything that is supposed to be tightened before the arbor is rotated, a high noise level due to air turbulence about the rotating cutterhead, danger of a breaking workpiece causing damage to the cutterhead or to the operator due to penetrating and then being flung from a radial pocket between knives or holders in the outer peripheral surface of the cutterhead, and the perceived need to provide strength through use of massive parts, resulting in weighty cutterheads.